The present invention relates to a projector in which a cover for lamp unit exchange, which is fixed to a chassis of the projector, may be removed for exchange of the lamp unit.
Projectors are per se known in the prior art, and are widespread, which irradiate light from a lamp upon an image display device, thus projecting an image displayed on this image display device upon a screen. This image display device may be a digital micro mirror device (DMD) or a liquid crystal display device.
This type of prior art projector comprises a projector chassis, a lamp door which can be fitted to the chassis and removed therefrom, a lamp unit which comprises a lamp, a fan which blows air into the lamp unit, and a lamp housing unit for installation of the lamp unit. This lamp unit housing unit is formed within the chassis of the projector, as a partitioned off storage space.
The lamp becomes hot due to emission of light. Due to this, in the above described projector according to the prior art, the lamp has been cooled by blowing air into the lamp unit with the fan. And the air which is to be exhausted after having air cooled the lamp is discharged to the exterior of the lamp unit housing unit from an exhaust aperture. This exhaust which is discharged from the exhaust aperture to the exterior of the lamp unit housing unit is then discharged to the exterior of the chassis by another fan.
It should be understood that, as a heat dissipation mechanism for such a projector, a mechanism in which fans are provided both before and after the light source is disclosed in Japanese Laid-Open Patent Publication Heisei 7-295097.
With a prior art type projector, in the state in which the lamp unit is installed to the lamp unit housing unit, sometimes air at high temperature leaks out from a gap at the junction portion between the lamp unit and the lamp unit housing unit. Due to this, sometimes heat has become trapped within the lamp unit housing unit described above, because of this escape of air at high temperature. As a result, sometimes the temperature within the lamp unit housing unit has become undesirably elevated. When the temperature within the lamp unit housing unit becomes high, the cooling efficiency of the lamp is deteriorated, which is not desirable.
Accordingly, there have been the problems of decrease of the light emission efficiency of the lamp, and of the life of the lamp becoming shorter. Furthermore, due to application of this undue heat to a lamp door made from resin provided in the neighborhood of the lamp unit, there has also been a fear that this lamp door may be softened and deformed.
The object of the present invention is to provide a projector which has a structure in which it is ensured that air at high temperature does not leak out from any gap at the joining portion between the lamp unit and the lamp housing unit.